changed server to not send pingplreport in response to "ping" command,

changed server to not send pingplreport in response to "ping" command,
because it confuses non-DP clients and older DP clients (resulting in
the message "unknown command pingplreport" flooding the console)
changed client to send "pings" command to DP7 protocol servers so that
it gets only the pingplreport output, avoiding any potential misparsing
of ping reports and reducing bandwidth a little.

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@7349 d7cf8633-e32d-0410-b094-e92efae38249